Giải nhanh giúp em với ạ Question Giải nhanh giúp em với ạ in progress 0 Môn Toán Maris 4 years 2020-10-29T20:29:40+00:00 2020-10-29T20:29:40+00:00 2 Answers 68 views 0
Answers ( )
`a)`
\(\left\{ \begin{array}{l}1 + \sqrt{1 – x} \ne 0\\1 – \sqrt{1 – x} \ne 0\\1 – x ≥ 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}\sqrt{1 – x} \ne -1 (l)\\\sqrt{1 – x} \ne 1\\x ≤ 1\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x \ne 0\\x ≤ 1\end{array} \right.\)
`=> D = (-∞; 1] \\ {0}`
`b)`
\(\left\{ \begin{array}{l}x ≥ 0\\x + 2\sqrt{x} + 1 \ne 0\\x – 1 \ne 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x ≥ 0\\(\sqrt{x} + 1)² \ne 0 (ld)\\x \ne 1\end{array} \right.\)
`=> D =[0; +∞) \\ {1}`
a) $y = \dfrac{1}{1 + \sqrt{1 – x}} + \dfrac{1}{1 – \sqrt{1 – x}}$
$y$ xác định $\Leftrightarrow \begin{cases}1 – x\geq 0\\\sqrt{1 – x} \ne 1\end{cases}\Leftrightarrow \begin{cases}x \leq 1 \\x \ne 0\end{cases}$
$\Rightarrow TXD: D =(-\infty;1]\backslash\left\{0\right\}$
Hoặc $D = (-\infty;0)\cup(0;1]$
b) $y = \dfrac{\sqrt x – 2}{x + 2\sqrt x + 1} – \dfrac{\sqrt x + 2}{x – 1}$
$y$ xác định $\Leftrightarrow \begin{cases}x \geq 0\\x – 1 \ne 0\end{cases} \Leftrightarrow \begin{cases}x \geq 0\\x \ne 1\end{cases}$
$\Rightarrow TXD: D = [0;+\infty)\backslash\left\{1\right\}$
Hoặc $D = [0;1)\cup (1;+\infty)$